Browsing by Author "Dawit Habtu (PhD)"

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    Developing a bidirectional smart charging station for the benefit of Electric utility and electric vehicle owners in Addis Ababa
    (Addis Ababa University, 2024-10) Habtamu Beyene; Dawit Habtu (PhD)
    Bidirectional electric vehicle charging systems have emerged as a revolutionary technology. This innovative solution allows two-way power flow. Currently, the use of electric vehicles has been increasing daily in Addis Ababa. This popularity of electric vehicles in Addis Ababa is expected to have a negative impact on existing electricity networks due to the increased energy demand from these vehicles on the the utility of the city. Moreover, there is a shortage of fast electric vehicles charging stations for electric vehicles owners in Addis Ababa. Consequently, this thesis aims to create a two-way smart charging station in Addis Ababa to provide advantages for both the electric utility company and owners of electric vehicles. The quadratic programming optimization technique is the method adopted to develop an intelligent charging plan in order to lower the cost of charging for both, electric utility and electric vehicles users. With this method, the utility load can be significantly leveled all day, because the electric vehicle owners can charge the electric vehicle at scheduled least loaded hours and the utility can obtain power from electric vehicle batteries for highest load balancing during smartly scheduled peak load hours. An algorithm is developed to regulate the energy flow between vehicle-to-grid and grid-to-vehicle operational modes. The validity of the proposed bidirectional charging station model and design was verified by MATLAB/Simulink. From the simulation result, it has been observed that electric vehicle can be charged at off-peak hours during the grid-to-vehicle scenario and also electric vehicles can provide active and reactive power support to the utility at peak load hours during the vehicle to grid scenario. As a result, with these two scenarios, load leveling can be realized. The purpose of reducing charging costs is realized by the adopted optimization techniques. With this optimization technique, electric vehicle users can benefit from supporting the grid during peak load hours and can charge the battery at a minimum of 15 minutes. The utility of a city can reduce about 50 MW of power in a day and can reduce large investment costs for upgrading the existing distribution network to meet new power demand due to the addition of electric vehicles to the grid system.
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    Strategic Scenario-Based Modeling for Optimal Electric Bus Charging Station Deployment in Addis Ababa
    (Addis Ababa University, 2025-10) Melkye Yifru; Dawit Habtu (PhD); J´er´emy Dumoulin (PhD) Co-Advisor
    The adoption of electric buses (EBs) is a critical step toward reducing greenhouse gas emissions and advancing sustainable urban mobility. In rapidly growing cities such as Addis Ababa, the deployment of an accessible, strategically planned, and grid compatible charging infrastructure is essential to support large-scale EB integration. However, the city currently lacks a charging system that aligns with its transport demand patterns, electricity supply characteristics, and renewable energy potential, creating a significant planning gap. This study investigates the spatial and temporal deployment of EB charging stations in Addis Ababa, aiming to ease peak loads, improve charger utilization, and enhance fleet reliability, thus strengthening utility efficiency and supporting sustainable urban mobility. It combines General Transit Feed Specification (GTFS) data and bus fleet characteristics with GIS-based simulation models (GTFS4EV and EV-Fleet-Sim) to estimate travel demand, energy requirements, and charger placement under depot, layover, on-route, and mixed charging strategies. The potential for solar photovoltaic (PV) integration is also assessed to enhance environmental performance and reduce reliance on the grid. Results indicate that each EB has an average daily energy demand of approximately 401 kWh (1.86 kWh/km). By 2030, EB deployment is projected to increase the city’s daily electricity load by 0.8%–2.4% depending on the electrification scenario. Charging strategies strongly influence the spatio-temporal distribution of demand: depot-only charging concentrates load during late-night hours; layover-only charging spreads it across the service day but remains spatially concentrated; and on-route charging disperses demand both spatially and temporally, though with feasibility limitations. Among the examined strategies, a mixed configuration of 47% depot, 27% layover, and 26% on-route offers the best balance between technical feasibility, operational, and cost efficiency. This strategy also shows the highest PV production alignment, achieving up to 40% self-sufficiency with an average energy coverage capability from 18.9% to 57.7% depending on the PV capacities per bus. While focused on Addis Ababa, the findings provide transferable insights for other cities pursuing EB electrification. The study demonstrates that strategic charging deployment integrated with renewable energy can optimize costs, reduce peak loads, and enhance system resilience. By quantifying trade-offs among economic, technical, and environmental objectives, this research offers a practical framework for policymakers and planners to design scalable, sustainable EB charging systems in diverse urban contexts.